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Culvert Replacement On the Ice Road Truckers Highway
An access road was built to the bottom of the ravine where a 50 by 50 foot pad was constructed. Water collecting in the low areas was diverted by pumping.
A 24 inch diameter Hammerhead pipe rammer was used to ram new 20 foot sections of pipe through the frozen soil. The machine develops up to 1,010 tons of force and can strike 150 blows per minute.
Steps in making the installation were to push in a section of new pipe, then remove soil and pieces of broken culvert with a horizontal directional drill using Harr Technologies patented culvert cleaning process. New pipe supported the weight of the earth above the culvert as earth and debris were removed.
To begin installation of the new pipe, an engaging tool was built to lock the hammer into the colletts that would fit the 96 inch pipe. "We set line and grade and started pounding," Harr said.
A Vermeer D50x100 horizontal directional drill with 50,000 pounds of pullback then used Harr Technologies culvert cleaning system to remove earth and pieces of the collapsed culvert.
"We removed 20 feet of material every time we welded on a new section of casing,” Harr explained. “This helped eliminate weight to aid the forward movement of the hammer pushing the casing.
“Perma frost is tough to work in. When the road was built 50 years ago, the fill used contained all kinds of debris which contributed to make the soil very unstable. We used a contoured pull bucket blade to remove the material with the directional drill providing a controlled pull, rather than an uncontrolled pull with a cable."
New spiral wound steel pipe was provided by Trinity Products, St. Louis, MO. The pipe is one inch thick and a 20 foot section weighs 14,000 pounds, making the logistics of moving and positioning the pipe with a large excavator in the extreme cold a challenge.
About 70-feet in, the hammer encountered a collapsed area where the casing began hitting multi plates of the existing culvert. “We then had to provide roof support and start precutting the multi plate,” Harr said. “Pounding distances were shortened to two feet at a time to protect workers who were 80 feet below the road's surface.”
The size of the 96 inch pipe was reduced by cutting out a section, using cables and lugs and making downsized pipe to telescope inside the pipe. After rebuilding engaging tools, pipe could be moved forward again. Another difficult area had to be mined by hand.